Generally in pressure atomizers the quality of atomization is improved by providing additional energy through a gas medium. Two common techniques are employed in the prior art, namely air assist and air blast. Air assist and air blast operate on a similar principle but differ in quantitative aspects of the ‘Air’ component. In the air assist technique, a small quantity of air at very high velocity (or pressure) is employed, whereas in the air blast technique a relatively large quantity of air at low velocities is employed. Both the quantity and velocity of air has to be understood in relative terms with respect to the related parameters of the liquid being atomized. In all cases, atomization depends on air-shear to break up the liquid column coming out of the orifice with some turbulence and may achieve some evaporation as well. It is understood that gas or air, achieve magnitude higher speeds at the same pressure compared to liquid being atomized at the same pressure.
There are also two common techniques defining where the air and liquid streams interact: ‘Internal Mixing Type’ where the two streams interact inside the atomizer body and ‘External Mixing Type’ where the two streams interact outside after the two streams exit their respective orifices. In both these concepts the atomization is due to a turbulent shear action of air moving over a liquid jet or liquid film.
Atomizers where two or more gas or air jets collide with a central liquid jet at a common focal point are also known. There are also further designs known where two or more coaxial composite jets collide at common focal point.